A team led by Victor P. Andreev, PhD, of Arbor Research Collaborative for Health in Ann Arbor, Michigan, conducted a cluster analysis using baseline urinary symptoms questionnaire data from 545 care-seeking women enrolled in the Lower Urinary Tract Dysfunction Research Network (LURN) Observational Cohort Study. They identified 4 clusters (F1 through F4). Women in cluster F1 did not report incontinence but experienced post-void dribbling, frequency, and voiding symptoms. Women in cluster F2 reported urgency incontinence as well as urgency and frequency and very minimal voiding symptoms or stress incontinence. Women in cluster F3 reported all types of incontinence, urgency, frequency, and very mild voiding symptoms. Women in cluster 4 report all LUTS at uniformly high levels.

All but 2 of 44 LUTS Tool questions and 8 American Urological Association Symptom Index questions differed significantly between at least 2 clusters, the investigators reported online ahead of print in The Journal of Urology.

In addition, all clusters included at least 1 member from each conventional group (continent, stress incontinence, urgency incontinence, mixed incontinence, and other incontinence), Dr Andreev and his colleagues reported.

The researchers noted that participants in cluster F1 previously would have been classified as overactive bladder (OAB) dry because they had minimal incontinence, “but that classification ignored the voiding and post-micturition symptoms.” Further, urgency is the defining diagnostic criterion for OAB, which is not central to this cluster, Dr Andreev and his team pointed out.

The reported symptoms of women in cluster F2 closely resemble the classical definition of wet OAB. Unlike the women in cluster F1, the women in cluster F2 have urgency incontinence as well as urgency and frequency, suggesting that OAB wet and dry are different clinical entities, they stated.

Women in cluster F3 had several kinds of incontinence plus urgency and frequency, suggesting that these women might have poor urethral function given that their storage symptoms are only modest and voiding symptoms non-existent, the authors noted. Therefore, they said, they would hypothesize that these women have poor outlet resistance consistent with stress urinary incontinence.

The women in cluster F4 have all LUTS, including voiding, storage, and incontinence reported at a severe degree, suggesting that these women have poor bladder function in addition to poor outlets, Dr Andreev and his collaborators said.

“Further validation is needed to determine whether management improves with this new classification,” the authors stated.